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Tracking Location Based on Water Isotope Ratios

...water molecules differ slightly in their isotope ratios depending on the minerals at their source. ...researchers found that water samples from 33 cities across the United State could be reliably traced back to their origin based on their isotope ratios. And because the human body breaks down water's constituent atoms of hydrogen and oxygen to construct the proteins that make hair cells, those cells can preserve the record of a person's travels.

Comments

Science meets NCIS (the TV version)... watched an episode yesterday where Abby helped to locate a kidnapped victim by examining hair samples and she specifically mentioned the isotope ratios of water. And I thought I was wasting my time :)

The linked article claims "such information could help prosecutors place a suspect at the scene of a crime, or prove the innocence of the accused". I would hope that 'being at the crime scene' would usually be defined more specifically than just being in the same city, otherwise a lot of people are going to need to 'prove their innocence'.

Right... And what does all that bottled water we consume do to skew the results? So, for forensic purposes, this data is worse than useless. For epidemiology studies or analysis, it may have some benefit.

Now I know if I travel around the country (or the world) and do not want the government to find out about it, I will have to bring bottled water from a local company along with me.

However, most food contain lots of water. And most people do not eat locally produced food. Suppose someone rarely drinks tap water, but drinks a lot of coffee made with bottled water from France? Will they be labeled as someone who snuck out of the US to France, then back home again? So it seems the scheme would have little value, other than fabricating charges against someone.

More useful to trace the origin of John Doe bodies that need identification.

Ideal to prove you were in that Taliban training camp, or Iraq.

Otherwise, I do not think this will be very useful for simple crimes. Too much "contamination" from imported foodstuff.

For those who think you can get around this with drinking bottled water. Then also stop drinking coffee and tea, and eating soup, boiled rice and pasta. And make sure bottled drinks are not from local sources. Next time you cook (or have something cooked), observe how much water you (or the cook) uses.

Market opportunity!
Sell water whose constituent atoms are highly skewed in their isotope ratios. A few milliliters a couple of times per day would obfuscate any local tags. A small bottle (TSA Approved!!) would last for weeks.

More important that just skewing the results by drinking water from France to make it look like you were in France, what you could do is, if you had the ratio table and selections of water that used each of the isotopes you could mix it to match a particular location and pretend to have gone there, no need to get water from there first.

I'm thinking about all the years that BATF thought that they could track an individual bullet to the specific manufacturing lot, based on the precise proportion of trace minerals in the batch. And the folks who were convicted upon that belief.

And how long it was before someone actually tested the process, and found that the difference in the proportions they were measuring within a single ingot was greater that that between the different lots they were purporting to measure.

How much does the proportion of isotopes differ, within each community? Does every well have an identical isotope signature? How much does it change over time? Does every well always have the same isotope signature?

This is old news - this type of technology has been used for many years to trace both groundwater sources and water contamination plumes among other things and the forensic plausibility of it was published some years ago.

It might be workable if someone only ate and drank things from their immediate location's water source, but given the water content in most processed foods and its quite variable sources,the final sorting of results would be murky at best.

Since as my screen name suggests, I own and operate a fusor, I'd bet my isotope ratios are a little bit unique. Guess I'll have to call off committing any big crimes for awhile -- or not. The probably higher ratio of deuterium in my blood stream from neutron capture would tend to indicate I drank a lot of seawater I guess, and I'm far from any ocean...

(www.coultersmithing.com for the fusor info)

The big myth I think is that any of the forensic stuff is as good as even the government claims it is, much less CSI kinds of shows, or that they pull it out of the drawer for most crimes at all -- they don't, and back in the day (early '70's) I'd seen the FBI labs for that -- dusty and most gear not working. No one there new how to work the voiceprint machine I happened to be expert on. Probably better now but hey -- there's a firehose of crimes out there to try and sip from.

I think they just pull that stuff out once they've already got someone they want put away, guilty of that particular crime or not. If you examined their chain of evidence at the same level as discovery in a lawsuit (which they won't let you do) you'd find a lot of places where samples are switched, improper techniques used, or just plain human mistakes somewhere along the line. So the function of the TV shows is to get juries to believe that junk, mainly.